shock watches

[Herb Chong [DCS]]

In article <1181 at houxm.UUCP> 59231ig at houxm.UUCP (I.GERSZBERG) writes:
><>
>We have those "shock watchers" on our disk packs.  We have never seen
>one of those things set yet!!!  One time we had a head crash, we took the
>(fortunately single) pack which had been destroyed and dropped it
>onto the floor from 2-3 feet....and the shock indicator STILL HAD NOT
>GONE OFF!!!!! EXPLAIN THAT ONE!  Then we dropped it again from a greater height
>and the thing finally showed (just a little though).  I'll
>let you draw your own conclusions from this experiment.
>
>Bob Switzer

i worked at a place once that askd me to do a little research into these
gadgets for testing how likely something was to be damaged when shipped in
a certain way.  most of these gadgets are little steel balls held in place
by springs or other variations on this.  almost all of them are rated
for 30G's or more before they trip.  small ones as low as 15G's are hard
to find and expensive.  we found that, after some calculations using
idealized numbers to mazimize acceleration, that a typical object dropped
from about 1m undergoes about 8 to 10 G's of acceleration.  in other
words, these things would trip only if the forces are large enough
to physically damage the exterior of the objects (in corrugated cardboard
boxes).  they aren't useful for other types.

Herb Chong...

I'm user-friendly -- I don't byte, I nybble....

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